Korean Patent Application Publication No. 10-2009-0052309 (May 25, 2009) discloses a “flow speed power generating apparatus using a flow speed of a tidal current”.
In the flow speed power generating apparatus using the flow speed of the tidal current, a pair of rollers is disposed at a certain interval so as to face each other at both ends of a buoyant object. Sprocket gears are disposed at the front and rear edges of the roller, respectively. A pair of caterpillar belts is connected to the two gears. The upper end and the lower end of the flow speed frame are mounted on the pair of caterpillar belts such that a plurality of flow speed frames are disposed between the pair of caterpillar belts. A flow speed plate and a balance belt are installed on the flow speed frame. The flow speed plate is spread when receiving a distributed force, and is folded by a hinge at the opposite side.
However, the flow speed power generating apparatus using the flow speed of the tidal current can receive a distributed force of water to convert energy from flowing water into rotational power that rotates a shaft only when a flow speed frame moves in the same direction as the water flow. When the flow speed frame moves in the opposite direction to the water flow, the flow speed frame acts as only a resistance, not increasing the rotational power of the shaft.